Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide (El-Serag, 2002, J Clin Gastroenterology 35:S72-78). During transformation from dysplastic regenerating hepatocytes to malignant hepatoma cells, several tumor-associated proteins are expressed that potentially could allow immune discrimination of malignant hepatocytes from surrounding non-tumor cells. Glypican-3 (GPC3), an oncofetal antigen re-expressed in a high frequency of neoplastic hepatocytes (Vidali, et al., 2008, J hepatol 48:399-406; Verbeeck, et al., 2008, J Clin Microbiol 46:1901-1906; Levrero, et al., 2009, J hepatol 51:581-592; Shaker, et al., 2009, Br J Dermatol 160:980-983) has emerged as a useful immunohistochemical diagnostic test (Anatelli, et al., 2008, Am J Clin Path 130:219-223; Baumhoer, et al., 2008, Am J Clin Path 129:899-906; Coston, et al., 2008, Am J Surg Pathol 32:433-444) and potential biomarker (Aburatani, 2005, J Gastroenterol 40, S16:1-6; Capurro, et al., 2005, Cancer Res 65:372; Capurro, et al., 2003, Gastroenterology 125:89-97; Hippo, et al., 2004, Cancer Res 64:2418-2423) for hepatocellular carcinoma. Glypican-3 appears critical for the association of growth factors such as IGF-2, BMP-7 and FGF-2 with growth factor receptors (Thapa, et al., 2009, J Paediatr Child Health 45:71-72; Zittermann, et al., 2010, Int J Cancer 126:1291-1301) but also may play an immunomodulatory role (Takai, et al., 2009, Cancer Biol Ther 8:2329-2338). Inhibition of glypican-3 function via knockdown (Ruan, et al., 2011, Int J Mol Med 28:497-503; Sun, et al., 2011, Neoplasia 13:735-747) or competition (Zittermann, et al., 2010, Int J Cancer 126:1291-1301; Feng, et al., 2011, Int J Cancer 128:2246-2247) has a profound negative effect on HCC cell line proliferation. Unlike any other tumor antigen associated with hepatocellular carcinoma to date, GPC3 is a glycophosphatidylinositiol-linked membrane-associated protein with a large extracellular domain attractive for antibody-directed therapy. An anti-glypican-3 antibody that induces antibody-dependent cytotoxicity has been shown to have anti-tumor effect in a xenograft animal model of hepatocellular carcinoma (Takai, et al., 2009, Cancer Biol Ther 8: 2329-38); this antibody has subsequently been humanized (Nakano, et al., 2010, Anticancer Drugs 21:907-916) and is entering human clinical trials. Thus the relative specific expressions of GPC3 on cell surface of malignant HCC tissues make it an attractive target for HCC tumor immunotherapy. However, the GPC3-specific T bodies, particularly the GPC3-specific scFv as targeting moieties, remain under development. The present invention addresses this need.